Profile of leisure-time physical activity and sedentary behavior in adults in Brazil: a nationwide survey, 2019

Abstract Objectives: to estimate the prevalence of leisure-time physical activity and sedentary behavior in adults in Brazil. Methods: this was a cross-sectional, population-based study carried out in a sample of 88,531 Brazilians, using data from the 2019 National Health Survey; leisure-time physical activity (overall and aerobic exercise) was measured according to the World Health Organization guidelines; the weighted prevalence and respective 95% confidence intervals (95%CI) of physical activity, physical inactivity and sedentary behavior were estimated. Results: according to the selected sample, 26.4% (95%CI 25.9;27.1) of Brazilian adults were physically active, 14.0% (95%CI 13.5;14.4) were insufficiently physically active and 59.5% (95%CI 58.8;60.2) were physically inactive; sedentary behavior ≥ 6 hours was reported by 30.1% (95%CI 29.5;30.8) of the population; only 8.6% (95%CI 8.2;8.9) met the recommendations for muscle-strengthening activities. Conclusion: most Brazilian adults were physically inactive and did not meet international recommendations for leisure-time physical activity and reduction in sedentary behavior.


INTRODUCTION
The World Health Organization (WHO), in its latest guidelines, recommends moderateintensity (≥ 150 minutes) or vigorous-intensity (≥ 75 minutes) aerobic physical activity a week, respectively. Adults should also do musclestrengthening activities two days a week, aiming at reducing risk of chronic diseases. In addition, it has recommended the reduction in sedentary behavior. 11 Population-based data on surveillance of leisure-time physical activity in Brazil require constant updates. The analyses of the most recent data have not explored the prevalence of leisure-time physical activity by aerobic physical activity and muscle strengthening modalities. [2][3][4][5] This analysis allows us to assess the levels of specif ic physical activity with reference to international recommendations. The objective of this study was to analyze data from the 2019 National Health Survey (Pesquisa Nacional de Saúde -PNS 2019), conducted by the Brazilian Ministry of Health. 3 The levels of leisure-time physical activity and sedentary behavior in Brazilian adults were estimated according to recent WHO recommendations.

Study design
This was a cross-sectional, population-based study among the participants of the PNS 2019.

Setting
The study comprised a cross-sectional analysis of data from the PNS 2019, a household survey conducted nationwide, both in urban and rural areas, composing a representative sample of the Brazilian population. The PNS 2019 used the three-stage conglomerate plan, with primary sampling unit stratification. These units consisted of census tracts or sets of tracts, and the selection was obtained by means of simple random sampling among those previously selected for the study. 6 The expected coefficient of variation (CV) was calculated based on values of indicators estimated f rom previous data obtained from the PNS 2013, using formulas for a sampling plan by simple random sampling and the effect of the sampling plan also estimated by the PNS 2013. 6 The CV was adjusted because the conglomerate plan is less efficient than the simple random sampling. In addition, the sample sizes of households and individuals were adjusted to fit the master sample, which serves as the sampling infrastructure for the research. The number of occupied households according to the Population Census was used as a measurement of the census tract size. The PNS 2019 was conducted by the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística -IBGE), in partnership

Main results
The majority of Brazilian adults were physically inactive, with 26.4% meeting the recommendations for leisure-time physical activity. Only 8.6% met the recommendations for musclestrengthening activities, and approximately one-third of them showed a sedentary behavior during most of their leisure time.

Implications for services
The data will help guide and update health promotion programs at the Primary Healthcare Center (PHC) that include the recommendations for physical activity, with a focus on leisure-time physical activity.

Perspectives
Further studies are needed to assess whether surveillance of levels of leisure-time physical activity and sedentary behavior in the Brazilian population can positively impact on the redesign of health promotion programs at PHCs.
A total of 94,111 households were randomly selected and 90,846 household residents, aged ≥ 15 years, were interviewed (response rate of 93.6%), and answered the questions in Module P contained in the 2019 PNS questionnaire regarding lifestyle information.

Participants
Participants aged ≥ 18 years were included in this analysis, with complete information about age, sex, leisure-time physical activity and sedentary behavior. Figure 1 shows the population flow included in the analysis of this study.

Variables
The study variables were: leisure-time physical activity (physically inactive, insuff iciently physically active and physically active), both for aerobic physical activity and musclestrengthening modalities, and sedentary behavior (in hours, categorized as 0 to < 4, 4 to < 6, 6 to < 8 and ≥ 8 hours).
Participation in any leisure-time physical activity in the last three months (yes/no), typical weekly frequency (0-7 days), duration (minutes or hours a day) and exercise modality performed (among 16 options) were self-reported.
The total weekly leisure-time physical activities, in minutes, was calculated and categorized according to the 2020 WHO physical activity guidelines, using the minimum threshold of 150 minutes/week for total leisuretime physical activity or moderate-to vigorousintensity aerobic physical activity. 1 Participants who reported doing muscle-strengthening activities two or more times a week were categorized as physically active for this modality, as established by WHO guidelines. 1

Physical activity and sedentary behavior in adults in Brazil
The response options for the modalities performed for categorizing physical activity are outlined below.
Daily screen time was measured as the self-reported time spent watching TV and using computer/laptop/tablet/cell phone during leisure time, and was operationalized as sedentary behavior. 7 Daily screen time was estimated by aggregating the responses to two questions: (i) On average, how many hours per day do you spend watching TV?; and (ii) How many hours of your free time per day (excluding work) do you usually spend using a computer, tablet or cell phone as a form of leisure, such as using social networks, watching news, videos, playing games, etc.?

Bias control
All participants who responded to the survey and met the inclusion criterion, age ≥ 18 years, answered the questions related to the variables of interest, therefore, there was no selection bias.

Statistical methods
Data were analyzed using the Stata statistical software (version 17.0, StataCorp LLC) and svy commands for analysis of complex samples, with weights for non-response adjustments; post-stratification adjustments were applied. The weighted prevalence estimates, described as percentage (%) and 95% confidence interval (CI), were stratified by sex and age group.

Ethical aspects
The study was approved by the National Research Ethics Committee on December 23, 2019, No. 3,529,376. Participants provided written informed consent prior to the interview.

RESULTS
The flow of participants included in this study is shown in Figure 1. All participants aged ≥ 18 years answered the questions related to the variables of interest (n = 88,531).
In the total sample size, 22 Table 1. Male participants showed higher levels of leisure-time physical activity in aerobic exercise modalities, when compared to female participants, while female participants showed higher levels of leisure-time physical activity in musclestrengthening modality (Table 1). However, the proportion of physically active male increased in the groups with higher sedentary behavior, while among female, physical inactivity was higher than among male in all sedentary behavior groups (Figure 2).

DISCUSSION
This study showed a low prevalence of leisuretime physical activity and a high prevalence of sedentary behavior in the Brazilian adult population. In the United States, a study indicated that 40.4% of the adult population met the WHO recommendations for leisuretime physical activity, while 44.6% remained inactive. 8 In that country, measures to address physical inactivity and sedentary behavior focused on primary care interventions. [9][10][11] Comparisons with other countries may be limited due to variation in methodologies for estimating physical activity. In the present study, only the leisure time domain was analyzed, whereas other countries such as England and China have analyzed other domains of physical activity, including transportation and occupational activities. 12,13 In this context, a 2018 estimate on global physical inactivity, based on previous population studies, showed that Brazil still had one of the highest levels of physical inactivity in Latin America. 14 Regarding the prevalence of musclestrengthening activities, data from the PNS 2019 revealed a worrying prevalence. Studies suggest that this modality of physical activity can also prevent metabolic and cardiovascular diseases in adults 15,16 and reduce mortality. [17][18][19] It is crucial that health policy actions prioritize muscle-strengthening modalities.
As for sedentary behavior, the percentage of people who meet the WHO recommendations for leisure-time physical activity increased as more time was spent in sedentary behavior among males, but not among females. Sociodemographic and occupational factors may have determined differences between sexes, favoring more time for physical activity among males. Data from prospective studies have indicated that increasing levels of leisuretime physical activity may counterbalance the detrimental effects of sedentary behavior on health. 7,17,19 This finding should be considered by police-makers as an opportunity to develop sex-specific interventions aimed at reducing sedentary behavior.  [20][21][22][23][24] In a systematic review on the effect of counseling and guidance interventions for physical activity in primary health care, the results ranged from no change to an increase of 88 minutes per week in the initial levels of participants' leisure-time physical activity. 24 However, a 2014 national study, which randomly selected 1,600 primary health care centers (PHC), showed that only 39.8% had physical activity promotion program. 25 These f indings, combined with our data, indicate that prevention programs in primary health care need to be updated in their priorities and expanded, with a focus on leisure-time physical activity.    0 to < 4h 0 to < 4h 4 to < 6h